WO2009092546A2

WO2009092546A2 - Kitchen exhaust ultraviolet system

Info

Publication number: WO2009092546A2
Application number: PCT/EP2009/000260
Authority: WO
Inventors: Alan Keogh; Chris Thompson; Brian J. Phillips
Original assignee: Niro-Plan Ag
Priority date: 2008-01-22
Filing date: 2009-01-16
Publication date: 2009-07-30
Also published as: WO2009092546A3

Abstract

A reaction chamber for a use in eliminating airborne grease particles and vapor in a kitchen exhaust system includes an ultraviolet (UV) lamp, a control system configured to control the UV lamp as well as measure air flow through the reaction chamber, a first opening configured to attach the reaction chamber to an existing ventilation hood, and a second opening configured to attach the reaction chamber to an existing exhaust duct.

Description

TITLE

KITCHEN EXHAUST ULTRAVIOLET SYSTEM

B. RELATED APPLICATIONS AND CLAIM OF PRIORITY

[0001] This application claims the priority benefit of U.S. Provisional Application no. 61/006,573 filed January 18, 2008 which is hereby incorporated by reference.

C-E. NOT APPLICABLE

F. BACKGROUND

[0002] The present application relates to kitchen exhaust systems. More particularly, the present application relates to a kitchen exhaust system that uses a reaction chamber having an ultraviolet lamp for removing grease, odor and their associated airborne particulates from passing through the exhaust system.

[0003] Commercial kitchens, especially quick service restaurants (QSRs), produce grease laden vapors as a result of their cooking processes. As exhaust air rises and cools, the grease will condense from a vapor to a solid and may accumulate on any surfaces it comes into contact with, e.g., ductwork used in an air exhaust system.

[0004] Ventilation hoods are used in a variety of applications, such as residential and commercial kitchens, laboratories, and industrial areas. Such hoods are typically included in kitchen exhaust systems to direct grease, odors and other air contaminants away from the cooking area or workspace. Depending on the application, an exhaust system may require a large motor and fan apparatus to deliver the exhaust capacity required to remove the contaminated air from the workspace. In areas where grease laden vapors are present, such as broilers, fryers, ovens, grills and other commercial cooking devices, the power required to operate the exhaust system, as well as the maintenance associated with cleaning the ventilation hood and any ductwork used in the exhaust system, may be substantial. Examples of such exhaust systems may be found in U.S. Patent Nos. 6,182,653; 6,235,090; 6,344,074; and 6,732,729, each of which is incorporated herein by reference. Additionally, as discussed above, the grease vapors will cool as they pass through the ductwork, and the grease will accumulate over time on the walls of the ductwork.

[0005] Many local and state regulations limit the odors and particulate matter that may be exhausted into the environment from a kitchen exhaust system. Often, ventilation hoods will include filters to reduce such undesirable emissions. However, the filters must be cleaned and/or changed often, and a dirty filter may create a fire hazard or an unhealthy working environment. Similarly, grease or other airborne particles may pass through the filter (i.e., the particles are too small to be filtered from the air) and solidify on the walls of the ductwork, potentially clogging the ductwork and causing a fire hazard. To overcome this problem, the use of ultraviolet light and ozone to reduce grease or odor in an exhaust has been included in ventilation hoods. For example, international patent application publication numbers PCT/GB03/00122 and PCT/GB01/00456, and U.S. Patent Nos. 4,750,917 and 5,997,619, each of which is incorporated herein by reference, describe the use of ultraviolet light to purify air that is passing through ventilation hoods. It is well known in the art that ultraviolet light, and particularly light having a wavelength of about 180-185 nm, produces ozone, which can purify air through oxidization. Many pollutants, such as grease and many odors, react with ozone and break down into water and other non-offensive compounds.

[0006] One problem with current air purification systems, and in particular purification systems that use ozone-producing ultraviolet bulbs, is that they may use excess power and overproduce ozone because they are operated even when not needed. Once turned on, they stay on until manually turned off or turned off by a timer, regardless of whether emissions actually occur. Another problem with current air purification systems using ultraviolet light is that the ventilation hood must be extensively modified or completely replaced to integrate the ultraviolet light purification system into the kitchen exhaust system.

G. SUMMARY

[0007] Before the present methods are described, it is to be understood that this invention is not limited to the particular systems, methodologies or protocols described, as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present disclosure which will be limited only by the appended claims.

[0008] It must be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. As used herein, the term "comprising" means "including, but not limited to."

[0009] In one general respect, the embodiments disclose a reaction chamber. The reaction chamber includes an ultraviolet (UV) lamp, a control system configured to control the UV lamp as well as measure air flow through the reaction chamber, a first opening configured to attach the reaction chamber to an existing ventilation hood, and a second opening configured to attach the reaction chamber to an existing exhaust duct.

[0010] In another general respect, the embodiments disclose an exhaust system. The exhaust system includes a ventilation hood configured to direct exhaust air away from a kitchen appliance; a reaction chamber, and an exhaust fan attached to the exhaust duct, wherein the exhaust fan turns in a direction such that exhaust air is pulled by the exhaust fan through the exhaust system. The reaction chamber includes an ultraviolet (UV) lamp, a control system comprising a logic control board having integrated components to control the UV lamp as well as measure air flow through the reaction chamber, a first opening positioned to attach the reaction chamber to the ventilation hood such that exhaust air is directed from the ventilation hood into the reaction chamber, and a second opening positioned to attach the reaction chamber to an exhaust duct such that exhaust air is directed from the reaction chamber into the exhaust duct

H. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Aspects, features, benefits and advantages of the present invention will be apparent with regard to the following description and accompanying drawings, of which:

[0012] FIG. 1 illustrates various embodiments of an exemplary exhaust system;

[0013] FIG. 2 illustrates various embodiments of an exemplary flowchart for the operation of an exemplary exhaust system such as the exhaust system shown in FIG. 1;

[0014] FIG. 3 illustrates various embodiments of an exemplary reaction chamber;

[0015] FIG. 4 illustrates various embodiments of an exemplary reaction chamber;

[0016] FIG. 5 illustrates various embodiments of an exemplary outer shell for a reaction chamber such as the reaction chamber shown in FIG. 3;

[0017] FIG. 6 illustrates various embodiments of an exemplary control panel for a reaction chamber; and

[0018] FIG. 7 illustrates various embodiments of an exemplary logic control board for a control panel such as the control panel shown in FIG. 6.

I. DETAILED DESCRIPTION [0019] In accordance with various embodiments, a reaction chamber may be constructed and mounted onto or next to existing ventilation hoods to provide a modular addition to existing kitchen exhaust systems that provides the benefits of an ultraviolet lamp air purification system as discussed above.

[0020] FIG. 1 shows an exemplary commercial kitchen exhaust system 100. System 100 directs exhaust air (represented by the white arrows A in FIG. 1) that may be laden with grease vapor created by kitchen appliance 102 to an area outside a building housing the commercial kitchen. Kitchen appliance 102 may be a stove, deep fryer, grill, griddle, broiler, or any other kitchen appliance that produces any odors or grease laden vapors to be exhausted to an area away from the appliance. It should be noted that a commercial kitchen is used herein merely by way of example, and the exhaust system described herein may be used in any environment where air is to be directed away from a particular area or device.

[0021] In system 100, grease vapor may be created by cooking surface 103. Exhaust air containing the grease laden vapor is pulled through ventilation hood 104 by exhaust fan 112. The exhaust air passes through hood filter 106, reaction chamber 108 where the air passes an ultraviolet (UV) lamp 109, then through ductwork 110 until the air is expelled through exhaust fan 112. This process is described in greater detail in the following discussion of FIG. 2.

[0022] FIG. 2 illustrates an exemplary flowchart describing the process of directing and expelling exhaust air in kitchen exhaust system 100. The process begins when grease laden vapor is created 202 at appliance 102. The grease laden vapor may be created 202 by cooking food, (e.g., a hamburger) on cooking surface 103 of appliance 102. After the grease is created 202, exhaust fan 112 pulls the air into ventilation hood 104 where the air may be filtered 204 by hood filters 106. Hood filters 106 may be designed to remove larger particles of grease vapor (e.g., hood filters may be manufactured that remove particles in the range of 8-10 μm in diameter), but may allow smaller particles (e.g., particles smaller than 8 μm in diameter) and vapors of grease to continue through exhaust system 100.

[0023] After filtering 202, the air passes through reaction chamber 108 where any present grease vapors or particles are oxidized 204 by the UV lamp contained in the reaction chamber. The UV lamp may be configured such that it produces a particular wavelength of light that produces ozone from the oxygen in the air. This produced ozone combines with the grease particles causing the grease-laden vapor to oxidize 206. As a result of the oxidation 206 process, the grease vapor is greatly reduced or eliminated entirely. Reaction chamber 108 and the oxidation process 206 are described below in greater detail in the discussions of FIGS. 3-7.

[0024] Following oxidation 206, the exhaust air is pulled 208 though ductwork 110 and expelled 210 through exhaust fan 112. As a result of the oxidation 206 process, any excess ozone created (e.g., any ozone that did not react with the grease laden vapor) is pulled 208 through the ductwork 110 and expelled 210 as well. This provides a safe environment for any workers in the kitchen (e.g., someone operating appliance 102), as the excess ozone is expelled 210 into the outside air where the ozone safely dissipates.

[0025] FIG. 3 shows an isolated view of an exemplary reaction chamber 108 when removed from exhaust system 100. Reaction chamber 108 includes an enclosure 302 that isolates the UV lamp (not shown in FIG. 3) safely from anyone operating the reaction chamber, or anyone operating a device around the reaction chamber (e.g., appliance 102). Access to the UV lamp may be provided via door 304. Enclosure 302 and door 304 may be made from the same material, such as stainless steel or aluminum, or any other suitable material depending on the application. If a reflective material is used, such as stainless steel, the UV light produced by the UV lamp may reflect off the inside surface of the enclosure 302, bouncing back towards the UV lamp creating another opportunity for the UV light to react with any airborne grease particles.

[0026] Door 304 may include a small window 305 which provides a means for visually confirming when the UV lamp is operating. Window 305 may be constructed of a UV impermeable material such as frosted or polarized glass for user safety.

[0027] Reaction chamber 108 may further include a control panel 306. Control panel 306 may include a logic control board containing various components such as a central processing unit, memory, input/output interfaces, etc. The logic control board is discussed in greater detail below in the discussion of FIG. 7.

[0028] Control panel 306 may also include a small screen for displaying information related to the operation of the reaction chamber. This related information may include current air flow rate, historic airflow rate (e.g., average air flow over the past 30 minutes, 24 hours, or any appropriate length of time), lamp life remaining, and any other relevant statistics related to the operation of the reaction chamber 108.

[0029] Reaction chamber 108 may further include opening 308. In this example, opening 308 is located on top of the reaction chamber 108. A second opening may be included on the bottom of reaction chamber 108 (not shown in FIG. 3). These two openings may be used to attach the reaction chamber 108 to an existing ventilation hood via the bottom opening and existing ductwork via the top opening 308. Various flanges may be provided to accommodate the openings to existing hoods and ductwork. For example, if the top opening 308 of the reaction chamber is 8 inches by 16 inches, and the existing ductwork is 10 inches by 12 inches, an appropriate flange may be fitted to the reaction chamber such that the reaction chamber attaches properly to the existing ductwork. Similarly, the top opening 308 may be specially sized to adapt directly to any existing ductwork. The bottom opening may be similarly adapted to fit onto any existing ventilation hood. A flange may be used to correct any size discrepancies, or the bottom opening of the reaction chamber may be specially cut to fit an existing ventilation hood.

[0030] Seals may also be provided to create an airtight seal between a reaction chamber and an existing ventilation hood or existing ductwork. For example, a rubber seal may be included that fits between an opening in the reaction chamber and the existing exhaust system component. For example, a rubber seal may be placed between the bottom opening of the reaction chamber and the opening in the ventilation hood to ensure there are no exhaust leaks. Similarly, silicone or any other suitable material may be used to create a seal.

[0031] By including openings that attach to existing components of an exhaust system, and a series of flanges and/or seals to ensure a correct fit, reaction chamber 108 may be quickly and cheaply adapted to existing kitchen exhaust systems rather than requiring the replacement of an expensive component such as the ventilation hood. Once a reaction chamber is integrated into an existing exhaust system, the reaction chamber may accept exhaust air from an existing ventilation hood through the reaction chamber's bottom opening, purify the exhaust in the reaction chamber via exposure to the UV lamp, and expel the exhaust into the existing ductwork through the reaction chamber's top opening.

[0032] Similarly, reaction chamber 108 may include various fittings and pipes 310 for use in adapting the reaction chamber to an existing fire extinguishing system. The fire extinguishing system, however, is non-essential to the system and methods described herein as novel.

[0033] FIG. 4 shows a bottom view of reaction chamber 108. In this example, UV lamp 404 may be placed in approximately the middle of reaction chamber 108, with equal distance on each side of the lamp to the walls of the reaction chamber. This arrangement may provide equal oxidation space on each side of the UV lamp as the exhaust air passes through the reaction chamber. UV lamp 402 may be of the quartz type that produces multiple wavelengths of UV light, specifically wavelengths in the "c" band class of light, also known as ultraviolet C, UVc, or light in the 100-280 nm range. By creating a first wavelength of light at approximately 254nm, photolysis is achieved. During photolysis, energy created by the UV lamp is transferred into the individual grease particles, breaking larger particles into smaller particles. Additionally, during this breaking process, chemically the grease particles are disrupted, and hydrogen and carbon atoms in the grease particles are left partially bonded. Simultaneously, UV lamp 402 may also produce a shorter wavelength UVc light, such as 185nm. UVc light with a wavelength of 185nm reacts with oxygen in the air to create relatively low levels of ozone (e.g., between 0.7 and 0.8 parts per million). The created ozone reacts with the partially bonded carbon and hydrogen atoms in the grease particles, causing oxidation or ozonation of the grease particles. The resulting product is a light ash. This light ash has little or no odor, and is not sticky like the grease particles. Therefore, the ash is easily passed through the exhaust system with little or no risk or accumulation on the inside surfaces of the ductwork.

[0034] The operation of UV lamp 402 may be controlled by ballasts 404. Power may be supplied to ballasts 404 by wire (or multiple wires arranged in a wire harness) 406. Wire 406 passes through hole 408 to the control system. The control system is described in greater detail in the discussions of FIGS. 6 and 7 below. A switch 410 may be connected to wire 406 as well. This switch may be used to detect the position of door 304 and may cut power to UV lamp 402 when the door is open. This provides added safety to anyone using reaction chamber 108.

[0035] Reaction chamber 108 may also include a removable filter 412. Depending on the application, this filter may be made of a fine steel mesh, fiberglass, or any other suitable material. This filter may add a retention feature to the reaction chamber. Filter 412 may provide additional UV light exposure time to larger particles that may have passed through the hood filters. The larger particles are retained by filter 412 and exposed to additional light from UV lamp 404.

[0036] An adjustable baffle 414 may also be included in reaction chamber 108. The adjustable baffle may slide in various directions to increase or decrease the size of either the top or bottom opening of reaction chamber 108. This may provide someone using the reaction chamber 108 to accurately control the rate of air flow through the chamber. It should be noted that in FIG. 4 both filter 412 and adjustable baffle 414 are shown on the top opening 308 of reaction chamber 108. It should be recognized that each of these components may be alternatively placed and are shown in this configuration by way of example only.

[0037] FIG. 5 illustrates reaction chamber 108 with various components removed such as control panel 306, door 304, pipes and fittings 310 and various electrical components discussed in FIG. 4. With door 304 removed, optional hinges 502 are shown. In this example, door 304 may open toward someone opening the door, latching at the top of reaction chamber 108. Also shown is switch 410 which may detect the position of door 304 and control the UV lamp accordingly. The switch 410 may be arranged such that a tab on the door 304 fits into the switch, thereby turning the switch on. When the door 304 is opened, this tab is removed from switch 410, which automatically shuts off the UV lamp.

[0038] Bottom opening 504, as discussed above, may be configured to adapt reaction chamber 108 to an existing ventilation hood, eliminating the need to replace the ventilation hood to achieve UV grease filtering. Similarly, flange 508, as discussed above as well, may be provided which aids in the adapting of reaction chamber 108 to existing ductwork via top opening 308.

[0039] With control panel 306 removed, hole 408 is shown through which wire 406 is passed to the control panel. Additionally, a flexible tube 506 may be provided. Tube 506 may be used to measure the air flow pressure in reaction chamber 108. Air flow information may be used by control panel 306 to alert a user to a possible air flow problem with the exhaust system.

[0040] FIG. 6 shows a close-up view of control panel 306. Included on control panel 306 is a liquid crystal diode (LCD) screen 602. It should be noted that an LCD screen is used herein merely by way of example, and other types of screens (e.g., organic light emitting diode (OLED)) may be used. Screen 602 may be used to display information related to the operation of reaction chamber 108 to a user. Exemplary information may include current lamp time, historic lamp time, remaining lamp time (based upon an estimate of the lamp's life expectancy), air flow, historic air flow, other attached reaction chambers, and any other relevant information.

[0041] A series of light emitting diode (LED) or other indicators 604 may also be included on control panel 306. Indicators 604 may be related to the operation of reaction chamber 108. For example, indicators 604 may include a green light, a yellow light and a red light. The green light may indicate the reaction chamber 108 is performing normally. The yellow light may indicate that there is a warning condition (e.g., air flow rate is low), and the red light may indicate that there is a fatal error and the reaction chamber 108 has shut down.

[0042] Additional controls 606 and 608 such as buttons, switches, levers, or touch screen sections may be provided to access various features of the reaction chamber 108. For example, control 606 may be used to turn reaction chamber 108 on or off. Additionally, control 606 may be used to turn on or off any additional reaction chambers attached to reaction chamber 108. Control 608 may be used to scroll through additional reaction chambers. Scrolling through additional reaction chambers with control 608 may change the information displayed on screen 602 to information relevant to the selected reaction unit. [0043] FIG. 7 illustrates an exemplary logic control board (LCB) 700 for use with reaction chamber 108. LCB 700 includes a central processor 702. Processor 702 operably connects to wire 406, and thus provides control for ballasts 404 and UV lamp 402. Processor 702 also connects to switch 410 via wire 406 and provides control to UV lamp 402, shutting off the UV lamp when switch 410 detects the door is open.

[0044] Processor 702 is also operably connected to display controller 704. Display controller 704 processing information received from processor 702 and configured the information to be displayed on screen 602 of control panel 306. Additionally, input/output (I/O) controller 706 is operably connected to processor 702. I/O controller 706 may be configured to receive signals from buttons 606 and 608 on control panel 306, and pass these signals to processor 702. Additionally, I/O controller 706 may be operable connected to I/O controllers on additional reaction chambers. This provides the option of making a single reaction chamber, e.g., reaction chamber 108, a master chamber that may be used to control additional slave reaction chambers via a central control panel, e.g., control panel 306 or reaction chamber 108. It should be noted that a slave reaction chamber may function without an LCB or control panel. The slave reaction chamber may be connected (e.g., wired or wirelessly) directly to the master reaction chamber, eliminating the need for any control at the slave reaction chamber.

[0045] Another component operably connected to processor 702 may be pressure monitor 708. Pressure monitor 708 may be connected to tube 506. Via this connection, pressure monitor 708 may monitor the air flow pressure of the exhaust air passing through reaction chamber 108 past the UV lamp. When initially installed and configured, a reaction chamber may be set with an acceptable air flow threshold. This threshold may be determined by a technician installing the reaction chamber based upon the type of ventilation hood being used along with the strength of the exhaust fan (which determined air pulling power of the fan) along with the dimensions of the existing ductwork. For example, the optimal air flow rate may be determined to be 750 cubic feet per minute. The reaction chamber may be set to have an optimal air flow rate of 750 cubic feet per minute, with an acceptable threshold of 10 percent (i.e., plus or minus 75 cubic feet per minute). Anything beyond this threshold may indicate a problem with the exhaust system such as a leak or a problem with the exhaust fan. By providing this information on the display of the reaction chamber, and additional component to measure air flow is not necessary.

[0046] It should be noted that the description of LCB 700 has been simplified to include only certain components. Additional components such as transistors, resistors, connectors, capacitors and other common circuitry components are optional and have been omitted from FIG. 7 for simplicity purposes.

[0047] It will be appreciated that the embodiments discussed above are merely shown by way of example. The individual products discussed above may be implemented in additional arrangements, such as differing configurations of components in the exemplary exhaust system. Additionally, the reaction chamber described herein may be modified to include additional internal components (e.g., multiple UV lamps or additional filters). Similarly, the connections between various reaction chambers as discussed above may be achieved via a wireless network in which case I/O controller 706 would incorporate wireless networking protocols and features. Similarly, individual reaction chambers may be connected to a data network allowing a user to access related information at a desktop computer or a portable computing device.

[0048] It will also be appreciated that the location of the reaction chamber in the exhaust system may vary depending on the environment used. For example, the reaction chamber may not be mounted directly on top of the ventilation hood; rather, the reaction chamber may be mounted in another location along the exhaust system from the hood. Similarly, the reaction chamber may be mounted off the side of the exhaust ductwork such that any ozone produced by the reaction chamber is pulled into the ductwork via the pressure created by the air flowing through the ductwork.

[0049] It will further be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

Claims

CLAIMS What is claimed is:

1. A reaction chamber comprising: an ultraviolet (UV) lamp; a control system configured to control the UV lamp as well as measure air flow through the reaction chamber; a first opening configured to attach the reaction chamber to an existing ventilation hood; and a second opening configured to attach the reaction chamber to an existing exhaust duct.

2. The reaction chamber of claim 1, wherein the UV lamp is configured to produce at least two wavelengths of UV light.

3. The reaction chamber of claim 1, wherein the UV lamp comprises quartz and emits light at least in the wavelengths of 254 nm and 185 nm.

4. The reaction chamber of claim 1, wherein the first opening further comprises at least one of a flange or a seal for adapting the reaction chamber to the existing ventilation hood.

5. The reaction chamber of claim 1 , wherein the second opening further comprises at least one of a flange or a seal for adapting the reaction chamber to the existing exhaust duct.

6. The reaction chamber of claim 1, wherein the second opening further comprises a filter.

7. The reaction chamber of claim 6, wherein at least one of the first or second openings further comprises an adjustable baffle.

8. The reaction chamber of claim 1, wherein the control system further comprises an input/output interface for communicating with additional reaction chambers.

9. The reaction chamber of claim 8, further comprising a user control interface.

10. The reaction chamber of claim 1, further comprising a door positioned such that when the door is open the UV lamp is exposed.

11. The reaction chamber of claim 10, wherein the door comprises a UV filtering glass viewing window.

12. The reaction chamber of claim 11 , further comprising a switch for operating the UV lamp based upon the position of the door, wherein the switch is turned off when the door is opened.

13. An exhaust system comprising: a ventilation hood configured to direct exhaust air away from a kitchen appliance; a reaction chamber comprising: an ultraviolet lamp; a control system comprising a logic control board having integrated components to control the ultraviolet (UV) lamp as well as measure air flow through the reaction chamber; a first opening positioned to attach the reaction chamber to the ventilation hood such that exhaust air is directed from the ventilation hood into the reaction chamber; and a second opening positioned to attach the reaction chamber to an exhaust duct such that exhaust air is directed from the reaction chamber into the exhaust duct; and an exhaust fan attached to the exhaust duct, wherein the exhaust fan turns in a direction such that exhaust air is pulled by the exhaust fan through the exhaust system.

14. The exhaust system of claim 13, wherein the UV lamp comprises quartz and emits light at least in the wavelengths of 254 nm and 185 nm.

15. The exhaust system of claim 13, wherein the first opening further comprises at least one of a flange or a seal for adapting the reaction chamber to the ventilation hood.

16. The exhaust system of claim 13, wherein the second opening further comprises at least one of a flange or a seal for adapting the reaction chamber to the exhaust duct.